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Date: Fri, 29 Feb 2008 14:29:06 +0100
From: Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>
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Subject: Re: [vdr] vdr 1.5.16 - minor problem in font.c
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On 02/29/08 01:04, Tobi wrote:
> Hello,
> 
> DrawText() in font.c uses the method Glyph() which may return a null pointer,
> but doesn't check the returned pointer.
> 
> I came across this bug, when checking a bug report from Sven Mueller:
> 
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=467512
> 
> When info.vdr contains an invalid character (like in the above example a 0xA0 -
> a Latin-1 NO-BREAK SPACE),  Glyph() returns null, which then causes a segfault
> when dereferencing the null-pointer.
> 
> The easiest way to fix this, would probably be to ignore such invalid
> characters, which is, what the attached two-line-patch will do. But maybe it's
> better to replace such characters with a default character - maybe a space or a '?'.

I also think showing some replacement character is best.

Can you please verify if the attached patch does this correctly?

If this works, I'd like to include it in version 1.6.0.

Klaus

--- font.c	2008/02/09 11:52:25	1.23
+++ font.c	2008/02/29 13:26:34
@@ -258,6 +258,11 @@
            uint sym = Utf8CharGet(s, sl);
            s += sl;
            cGlyph *g = Glyph(sym, AntiAliased);
+           if (!g) {
+              g = Glyph('?', AntiAliased);
+              if (!g)
+                 continue;
+              }
            int kerning = Kerning(g, prevSym);
            prevSym = sym;
            uchar *buffer = g->Bitmap();